dict
#d = {'huangliag':95,'lihui':75,'xueqi':85,'weijie':85,'candong':90}
#print(d['lihui'])
#d.pop('huangliag')
#print(d)
#set
#s1 = set([1,2,3,4])
#s2 = set([4,5,6])
#print(s1 | s2)
#s1.remove(4)
#s1.add(5)
#print(s)
